package com.example.wnn.utils;


import cn.hutool.core.util.ObjectUtil;
import com.example.wnn.develop.ieport.export.ExportEntityMap;
import com.example.wnn.develop.ieport.export.ExportProperty;
import lombok.extern.slf4j.Slf4j;
import org.apache.poi.hssf.usermodel.*;
import org.apache.poi.ss.usermodel.Footer;
import org.apache.poi.ss.usermodel.Header;

import javax.servlet.http.HttpServletResponse;
import java.io.BufferedOutputStream;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.math.BigDecimal;
import java.net.URLEncoder;
import java.text.SimpleDateFormat;
import java.util.*;

@Slf4j
public class ExportExcelUtils {

    /**
     * 导出Excel
     *
     * @param excelName 要导出的excel名称
     * @param list      要导出的数据集合
     * @param c         中英文字段对应Map，即要导出的excel表头
     * @param response  使用response可以导出到浏览器
     * @param <T>
     */
    public static <T> void export(String excelName, List<T> list, Class<T> c, HttpServletResponse response) {
        // 设置日期格式
        SimpleDateFormat df = new SimpleDateFormat("yyyyMMddHHmmss");
        // 设置默认文件名为当前时间：年月日时分秒
        if (excelName == null || excelName == "") {
            excelName = df.format(new Date());
        } else {
            excelName = excelName + df.format(new Date());
        }

        try {
            //创建一个WorkBook,对应一个Excel文件
            HSSFWorkbook wb = new HSSFWorkbook();
            //在Workbook中，创建一个sheet，对应Excel中的工作薄（sheet）
            HSSFSheet sheet = wb.createSheet(excelName);
            //设置 边距、页眉、页脚
            HSSFPrintSetup printSetup = sheet.getPrintSetup();
            //打印方向，true：横向，false：纵向(默认)
            printSetup.setLandscape(true);
            printSetup.setHeaderMargin(0.2);
            printSetup.setFooterMargin(0.2);
            //设置打印缩放为88%
            ///printSetup.setScale((short) 55);
            printSetup.setFitHeight((short) 0);
            printSetup.setFitWidth((short) 1);
            //列从左向右显示②
            /// printSetup.setLeftToRight(true);
            // 纸张
            printSetup.setPaperSize(HSSFPrintSetup.A4_PAPERSIZE);
            // 页边距（下）
            sheet.setMargin(HSSFSheet.BottomMargin, 0.8);
            // 页边距（左）
            sheet.setMargin(HSSFSheet.LeftMargin, 0);
            // 页边距（右）
            sheet.setMargin(HSSFSheet.RightMargin, 0);
            // 页边距（上）
            sheet.setMargin(HSSFSheet.TopMargin, 0.8);
            //设置打印页面为水平居中
            sheet.setHorizontallyCenter(true);
            sheet.setVerticallyCenter(true);
            sheet.setAutobreaks(false);
            sheet.setFitToPage(false);
            Footer footer = sheet.getFooter();
            //设置页数
            footer.setCenter("第" + HeaderFooter.page() + "页，共 " + HeaderFooter.numPages() + "页");
            Header header = sheet.getHeader();
            //自定义页眉,并设置页眉 左中右显示信息
            //居中
            ///header.setCenter("Center Header");
            //靠左
            header.setLeft(HSSFHeader.font("宋体", "") +
                    HSSFHeader.fontSize((short) 16) + excelName + ".xlsx");
            //靠右
            ///header.setRight(HSSFHeader.font("Stencil-Normal", "Italic") +
            ///HSSFHeader.fontSize((short) 16) + "Right w/ Stencil-Normal Italic font and size 16");

            //创建单元格，并设置值表头 设置表头居中
            HSSFCellStyle style = wb.createCellStyle();
            //设置边框
            //下边框
            style.setBorderBottom(HSSFCellStyle.BORDER_THIN);
            //左边框
            style.setBorderLeft(HSSFCellStyle.BORDER_THIN);
            //上边框
            style.setBorderTop(HSSFCellStyle.BORDER_THIN);
            //右边框
            style.setBorderRight(HSSFCellStyle.BORDER_THIN);
            //自动换行
            ///style.setWrapText(true);
            //创建一个居中格式
            style.setAlignment(HSSFCellStyle.ALIGN_CENTER);
            //上下居中
            style.setVerticalAlignment(HSSFCellStyle.VERTICAL_CENTER);
            //设置字体
            HSSFFont font = wb.createFont();
            font.setFontName("宋体");

            style.setFont(font);
            // 填充工作表
            //获取需要转出的excel表头的map字段
            LinkedHashMap<String, String> fieldMap = new LinkedHashMap<>();
            //循环注解里面的值 填入Link集合
            Field[] declaredFields = c.getDeclaredFields();
            //获取属性对应的枚举类
            LinkedHashMap<String, Class> converterMap = new LinkedHashMap<>();

            for (Field declaredField : declaredFields) {
                //获取注解对象
                ExportEntityMap declaredAnnotation = declaredField.getDeclaredAnnotation(ExportEntityMap.class);
                ExportProperty converterAnnotation = declaredField.getDeclaredAnnotation(ExportProperty.class);
                if (declaredAnnotation != null) {
                    fieldMap.put(declaredAnnotation.EnName(), declaredAnnotation.CnName());
                    if (converterAnnotation != null) {
                        converterMap.put(declaredAnnotation.EnName(), converterAnnotation.Converter());
                    }
                }
            }
            fillSheet(sheet, list, fieldMap, style, converterMap);
            // 设置response头信息
            response.reset();

            try {
                log.info("excelName:{}", excelName);
                String fileName = URLEncoder.encode(excelName + ".xlsx", "UTF-8");
                //尝试解决Excel跨域问题
                response.setHeader("Access-Control-Expose-Headers", "Content-Disposition");
                response.setHeader("Pragma", "no-cache");
                response.setHeader("Cache-Control", "no-cache");
                response.setHeader("Content-Type","application/force-download");
                response.setHeader("Content-Type","application/vnd.ms-excel");
                response.setHeader("Content-Disposition", "attachment; filename=" + fileName);
                response.addHeader("Access-Control-Allow-Origin", "*");
                response.addHeader("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE");
                response.addHeader("Access-Control-Allow-Headers", "Content-Type");
                //让服务器告诉浏览器它发送的数据属于excel文件类型
                response.setContentType("application/vnd.ms-excel;charset=utf-8");

            } catch (UnsupportedEncodingException e1) {
                log.error("导出excel失败，异常：", e1);
            }
            //将文件输出
            OutputStream outputStream = new BufferedOutputStream(response.getOutputStream());
            //response.setContentType("application/octet-stream");
            response.flushBuffer();

            wb.write(outputStream);
            outputStream.flush();
            outputStream.close();
        } catch (Exception e) {
            log.error("导出Excel失败，异常：", e);
        }
    }


    /**
     * 根据字段名获取字段对象
     *
     * @param fieldName 字段名
     * @param clazz     包含该字段的类
     * @return 字段
     */
    public static Field getFieldByName(String fieldName, Class<?> clazz) {
        // 拿到本类的所有字段
        Field[] selfFields = clazz.getDeclaredFields();
        // 如果本类中存在该字段，则返回
        for (Field field : selfFields) {
            //如果本类中存在该字段，则返回
            if (field.getName().equals(fieldName)) {
                return field;
            }
        }
        // 否则，查看父类中是否存在此字段，如果有则返回
        Class<?> superClazz = clazz.getSuperclass();
        if (superClazz != null && superClazz != Object.class) {
            //递归
            return getFieldByName(fieldName, superClazz);
        }
        // 如果本类和父类都没有，则返回空
        return null;
    }

    /**
     * 根据字段名获取字段值
     *
     * @param fieldName 字段名
     * @param o         对象
     * @return 字段值
     * @throws Exception 异常
     */
    public static String getFieldValueByName(String fieldName, Object o)
            throws Exception {
        String fieldValue = null;
        //根据字段名得到字段对象
        Field field = getFieldByName(fieldName, o.getClass());
        //如果该字段存在，则取出该字段的值
        if (field != null) {
            //类中的成员变量为private,在类外边使用属性值，故必须进行此操作
            field.setAccessible(true);
            //获取当前对象中当前Field的value
            fieldValue = field.get(o) == null ? "" : field.get(o).toString();
            String fieldType = field.getGenericType().toString();
            if ("class java.math.BigDecimal".equals(fieldType) || "class java.lang.Double".equals(fieldType)) {
                fieldValue = new BigDecimal(fieldValue).setScale(2, BigDecimal.ROUND_HALF_UP).toString();
            } else if ("class java.time.LocalDateTime".equals(fieldType) || "class java.time.LocalDate".equals(fieldType)) {
                fieldValue = fieldValue.replace("T", " ");
            }
        } else {
            throw new Exception(o.getClass().getSimpleName() + "类不存在字段名 "
                    + fieldName);
        }
        return fieldValue;
    }

    /**
     * 根据带路径或不带路径的属性名获取属性值,即接受简单属性名， 如userName等，又接受带路径的属性名，如student.department.name等
     *
     * @param fieldNameSequence 带路径的属性名或简单属性名
     * @param o                 对象
     * @return 属性值
     * @throws Exception 异常
     */
    public static String getFieldValueByNameSequence(String fieldNameSequence,
                                                     Object o) throws Exception {
        String value = null;
        // 将fieldNameSequence进行拆分
        String[] attributes = fieldNameSequence.split("\\.");
        if (attributes.length == 1) {
            value = getFieldValueByName(fieldNameSequence, o);
        } else {
            // 根据数组中第一个连接属性名获取连接属性对象，如student.department.name
            Object fieldObj = getFieldValueByName(attributes[0], o);
            //截取除第一个属性名之后的路径
            String subFieldNameSequence = fieldNameSequence
                    .substring(fieldNameSequence.indexOf(".") + 1);
            //递归得到最终的属性对象的值
            value = getFieldValueByNameSequence(subFieldNameSequence, fieldObj);
        }
        return value;
    }

    /**
     * 向工作表中填充数据
     *
     * @param sheet        excel的工作表名称
     * @param list         数据源
     * @param fieldMap     中英文字段对应关系的Map
     * @param style        表格中的格式
     * @param converterMap 属性对应转化器的Map
     * @throws Exception 异常
     */
    public static <T> void fillSheet(HSSFSheet sheet, List<T> list,
                                     LinkedHashMap<String, String> fieldMap, HSSFCellStyle style, LinkedHashMap<String, Class> converterMap) throws Exception {
        // 定义存放英文字段名和中文字段名的数组
        String[] enFields = new String[fieldMap.size()];
        String[] cnFields = new String[fieldMap.size()];
        // 填充数组
        int count = 0;
        for (Map.Entry<String, String> entry : fieldMap.entrySet()) {
            enFields[count] = entry.getKey();
            cnFields[count] = entry.getValue();
            count++;
        }

        //存储最大列宽
        Map<Integer, Integer> maxWidth = new HashMap<>(16);
        HSSFRow row = sheet.createRow(0);
        HSSFCell cell = null;
        // 填充表头
        for (int i = 0; i < cnFields.length; i++) {
            cell = row.createCell(i);
            cell.setCellValue(cnFields[i]);
            cell.setCellStyle(style);
            sheet.autoSizeColumn(i);
            //设置自适应宽高
            maxWidth.put(i, cell.getStringCellValue().getBytes().length * 256 + 200);
        }
        // 填充内容
        for (int index = 0; index < list.size(); index++) {
            row = sheet.createRow(index + 1);
            // 获取单个对象
            T item = list.get(index);
            int j = 0;
            for (int i = 0; i < enFields.length; i++) {
                HSSFCell createCell = row.createCell(j);
                String objValue = getFieldValueByNameSequence(enFields[i], item);
                //获取属性对应的枚举类
                Class<Enum> converterClazz = converterMap.get(enFields[i]);
                objValue = convertFieldValue(objValue, converterClazz);
                String fieldValue = objValue == null ? "" : objValue;
                cell = row.createCell(i);
                createCell.setCellValue(fieldValue);

                int length = createCell.getStringCellValue().getBytes().length * 256 + 200;
                //这里把宽度最大限制到15000
                if (length > 15000) {
                    length = 15000;
                }
                maxWidth.put(j, Math.max(length, maxWidth.get(j)));
                j++;
                createCell.setCellStyle(style);
            }
        }

        // 列宽自适应
        for (int i = 0; i < cnFields.length; i++) {
            sheet.setColumnWidth(i, maxWidth.get(i));
        }
    }

    /**
     * 转换属性值
     *
     * @param objValue       :
     * @param converterClazz :
     * @return java.lang.String
     **/
    private static <T> String convertFieldValue(String objValue, Class<Enum> converterClazz) throws Exception {
        if (ObjectUtil.isNotNull(converterClazz)) {
            //获取所有枚举实例
            Enum[] enumConstants = converterClazz.getEnumConstants();
            //根据方法名获取方法
            Method valueMethod = converterClazz.getMethod("getValue");
            if (ObjectUtil.isNull(valueMethod)) {
                throw new Exception(converterClazz.getSimpleName() + "类找不到getValue()方法");
            }
            Method descMethod = converterClazz.getMethod("getDescription");
            if (ObjectUtil.isNull(descMethod)) {
                throw new Exception(converterClazz.getSimpleName() + "类找不到getDescription()方法");
            }
            for (Enum enumFiled : enumConstants) {
                //执行枚举方法获得枚举实例对应的值
                Object value = valueMethod.invoke(enumFiled);
                Object description = descMethod.invoke(enumFiled);
                if (ObjectUtil.equal(objValue, value.toString())) {
                    objValue = description.toString();
                }
            }
        }
        return objValue;
    }



}
